<!DOCTYPE HTML>
<svg width="400" height="400">
    <defs>
        <rect id="clip1Shape" x="0" y="0" width="50" height="100"/>
        <rect id="clip2Shape" x="50" y="0" width="50" height="100"/>
        <!-- Should not contribute to the clip. -->
        <rect id="clip3Shape" style="display:none" x="100" y="0" width="50" height="100"/>
        <clipPath id="clipUnion">
            <use xlink:href="#clip1Shape"/>
            <use xlink:href="#clip2Shape"/>
            <use xlink:href="#clip3Shape"/>
            <!-- Should not contribute to the clip. -->
            <rect style="display:none" x="150" y="0" width="50" height="100"/>
        </clipPath>
    </defs>
    <rect width="300" height="100" clip-path="url(#clipUnion)" fill="green"/>
</svg>
